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By FGT1958 - 4 Years Ago
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I am working on a basket-case 55 TBird. It came to me in parts and I am slowly trying to resurrect it. It has a 292 YBlock that was sent out to the machine shop, along with the cylinder heads, crank, rods, heads, rockers and valves. The block and heads were cleaned up and pressure tested. The block bored 60 over with new pistons and rings. Heads redone with new valves, springs and rocker shafts. I got it back and put it all together using the YBlock rebuild book and of course, the various YBlock internet sites. Got it installed in the frame and wanted to get it started before I started hanging everything else on it. It seemed a little hard to turn over by hand, but I attributed that to the new rings and compression. When I installed the starter and tried, is seemed to turn over slowly without the plugs in it and very slowly with the plugs in it. I thought it may be the 60 year old starter, so I rebuilt that...no joy. So I bought a new 12volt starter and installed that. A little better, but not spinning it fast enough to start it. So I went looking for other issues. I have consistently pressurized the oil system and have oil up to the heads. Some folks I talked to have suggested the rings might be too tight, but according to my notes, they are within spec. Others have suggested the pushrods being adjusted too tight. So, I pulled the valve covers and pulled all the pushrods. They all look good, but I have 2 different types of pushrods. One is skinny and solid and the other is fat and tubular..  I think one is old style and one is new... But that got me thinking and I remembered that the block is not original to the car. My research shows that it is a 1959 292. The pushrods are for a 1955 292, while 1956 thru 1962 uses slightly shorter pushrods. The heads are 1955 292 TBird heads. Could the difficulty in spinning the engine be a result of the pushrods being too long? If not, then I guess I would need to tear it back down and build it back up again, double checking my clearances on all the bearing surfaces. Thanks for any help or suggestions you may have! Frank
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By Cliff - 4 Years Ago
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Hi, first check and make sure the flywheel bolts are not to long (Hitting the seal retainer), next (likely) check the cam shaft end play, also make sure the cam plug at the rear of the block is not driven in to far (hitting the cam), the last thing to check did you put the rod caps on correctly? not turned around or switched from rod to rod?
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By blocky - 4 Years Ago
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i think you may be back to checking clearances. did you line bore the block and did the crank spin by hand afterwards? same for the cam .
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By Florida_Phil - 4 Years Ago
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I doubt the push rods would cause this problem. If so, you would have noticed this when you adjusted the valves. Did the motor turn over easily when you had it on the engine stand? Did you check the rod and main clearances? Did you check the cam end play? I have seen a few YBlocks where the cam was too tight in the cam bearings. With the plugs out, you should be able to turn the engine over with a breaker bar by hand. If not, don't try to start the engine until you find out what's going on.
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By 55 GLASS TOP - 4 Years Ago
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Did the crankshaft turn smoothly as you installed each piston. It had to be turned to tighten the end caps. Is the transmission on the back or did you only put the engine in the frame. I was wondering if it’s some transmission interference problem
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By '49 bomb! - 4 Years Ago
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I don't know if this is going to be any help, but I had the same experience when I rebuilt my y block. I did a stock rebuild. And when I was finally ready to start it, I had a brand new battery I had another vehicle given me a jump, plus I had my battery charger on very high amperage! I finally did get it to start but it was a real struggle! I never did find out what the problem was,all I know it's running fine now. And from me giving it all that extra amperage I burned a starter up and it actually caught on fire on me. So long story short, make sure you don't get your starter to hot.
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By oldcarmark - 4 Years Ago
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FGT1958 (1/18/2020)
I am working on a basket-case 55 TBird. It came to me in parts and I am slowly trying to resurrect it. It has a 292 YBlock that was sent out to the machine shop, along with the cylinder heads, crank, rods, heads, rockers and valves. The block and heads were cleaned up and pressure tested. The block bored 60 over with new pistons and rings. Heads redone with new valves, springs and rocker shafts. I got it back and put it all together using the YBlock rebuild book and of course, the various YBlock internet sites. Got it installed in the frame and wanted to get it started before I started hanging everything else on it. It seemed a little hard to turn over by hand, but I attributed that to the new rings and compression. When I installed the starter and tried, is seemed to turn over slowly without the plugs in it and very slowly with the plugs in it. I thought it may be the 60 year old starter, so I rebuilt that...no joy. So I bought a new 12volt starter and installed that. A little better, but not spinning it fast enough to start it. So I went looking for other issues. I have consistently pressurized the oil system and have oil up to the heads. Some folks I talked to have suggested the rings might be too tight, but according to my notes, they are within spec. Others have suggested the pushrods being adjusted too tight. So, I pulled the valve covers and pulled all the pushrods. They all look good, but I have 2 different types of pushrods. One is skinny and solid and the other is fat and tubular.. I think one is old style and one is new... But that got me thinking and I remembered that the block is not original to the car. My research shows that it is a 1959 292. The pushrods are for a 1955 292, while 1956 thru 1962 uses slightly shorter pushrods. The heads are 1955 292 TBird heads. Could the difficulty in spinning the engine be a result of the pushrods being too long? If not, then I guess I would need to tear it back down and build it back up again, double checking my clearances on all the bearing surfaces. Thanks for any help or suggestions you may have! Frank
Was the Engine dis-assembled when You got it? I seem to recall there were 2 different Camshaft Thrust Plates used on Y Blocks. If the Camshaft end play is less than Specs because the wrong Thrust Plate was used that may be your Problem. With Plugs out You should be able to turn it over using a Ratchet and Socket. If You can't U need to think about rechecking your clearances. Something is wrong Somewhere.
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By Florida_Phil - 4 Years Ago
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I ran into the thrust plate issue when I built my motor. The motor that came with my TBird was a Frankenstein mixture of parts. I used that block with a double roller timing chain. When I torqued down the cam bolt, the cam assembly bound up. Luckily, I had another engine nearby that had never been disassembled. I swapped cam thrust plates and the cam end play was perfect. I could have shaved the other thrust plate, but I got lucky.
If you run an engine that binds, it may start. There is a good chance you will have problems down the road. Building an engine is about proper assembly and checking clearances. I never assume a machinist did their job right. It's better to doubt their work and check it twice.
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By Ted - 4 Years Ago
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There are a lot of good responses to this and each one of them needs to be checked and/or eliminated from the list. Add this to the list. You don’t mention what transmission but if an automatic, then there’s potentially not enough free play when the transmission was bolted up to the engine with the crankshaft now being jammed up against the main thrust bearing in the block.
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By FGT1958 - 4 Years Ago
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Thank you all for the responses! The engine was disassembled when I got it.
I did check the clearances when for the rods and mains when I was assembling. Also the endplay on the cam.
All good responses, and again, Thank You! I will start taking it back down and re-checking the everything again. You all have given me a lot to think about.
Frank
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By oldcarmark - 4 Years Ago
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FGT1958 (1/19/2020)
Thank you all for the responses! The engine was disassembled when I got it. I did check the clearances when for the rods and mains when I was assembling. Also the endplay on the cam. All good responses, and again, Thank You! I will start taking it back down and re-checking the everything again. You all have given me a lot to think about. Frank
If it was disassembled were the Main Caps off? They are not identified from the Factory as to position. Even though you checked clearance are the Caps in correct position? Were the mains line bored at Machine Shop?
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By 2721955meteor - 4 Years Ago
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try a mixture of gas and oil,50/50 squirt it down the card while trying to start,once you get a cough the engine should loosen up . if not then you have big issues. i have used this first start procedures for years,it insures valve guedes ,rings , pistons get instance lube.
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By weasel - 4 Years Ago
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If its a standard, tow it around the block in gear.
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By Hoosier Hurricane - 4 Years Ago
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Since you are going to look into the engine again, start by removing the timing chain/gears. Then turn the crank. That will tell you whether you need to look into the crankshaft or camshaft portion of the engine. Oh, take the rocker shafts off first so you don't crash a piston into a valve.
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By FORD DEARBORN - 4 Years Ago
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I understand your frustrations with this after going through all this trouble, work and expense then not have it all come together properly. At the moment, I can't offer more than what was already offered and wish you the very best. However, please keep in mind the proper method and procedure for flat tappet camshaft and lifter break-in. IMHO, any engine that requires excessive torque to rotate and is forced to do so may not have a happy ending. Hope you find the cause and it's something simple, JEFF................
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By oldcarmark - 4 Years Ago
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Hoosier Hurricane (1/19/2020)
Since you are going to look into the engine again, start by removing the timing chain/gears. Then turn the crank. That will tell you whether you need to look into the crankshaft or camshaft portion of the engine. Oh, take the rocker shafts off first so you don't crash a piston into a valve.
That's excellent Advice. Try and narrow down where the Problem might be without taking everything apart.
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By darrell - 4 Years Ago
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i put a 312 in a 56 this past summer and it turned over to slow to start.the car had sit for 10 years and the motor almost as long.in the end corrosion around the ends of the battery cables was the cause.
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By miker - 4 Years Ago
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There's a very similar post over on the HAMB, which I suspect is you. You note you're trying to start the engine with a battery charger set on the "engine start" setting of 225 amps IIRC. That won't do it. When I had a fleet I had a charger that would, but it was so big it was mounted on a hand truck to move it around. You need a decent, fully charged battery that will hold the cranking amps long enough to fire the engine. I just went thru this with a bad battery (one year old, expensive Odyssey, showed 12 volts). Wouldn't crank my 312 even with the charger on start. When they tested it it was almost at the bottom of the scale for bad. Replaced it for free. Problem solved.
So get a good battery in the circuit, and if necessary jump it to a battery on a running vehicle till you see if it cranks. As stated above, don't keep going till you cook the starter.
Edit: I should have said crank rather than start the engine.
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By 1960fordf350 - 4 Years Ago
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Do you have a ground strap attached from the engine to the body? I also have a ground from the generator bracket to the frame. A bad ground really can cause frustrations. Hopefully you find a simple solution.
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By PF Arcand - 4 Years Ago
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Did you install the cam yourself? If no, it's been reported here & elsewhere that some blocks have misalligned Cam bearing castings. Or did you have difficulty installing the Cam into the bearings? If so, Ted or others here might have suggestions to cure the issue..
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By '49 bomb! - 4 Years Ago
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I love the beautiful cars pictured in this post, the convertible and the bird! Very nice machines men....
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By Florida_Phil - 4 Years Ago
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PF Arcand (1/21/2020)
Did you install the cam yourself? If no, it's been reported here & elsewhere that some blocks have misalligned Cam bearing castings. Or did you have difficulty installing the Cam into the bearings? If so, Ted or others here might have suggestions to cure the issue..
Years ago I built a 312 engine for a 1957 Victoria. I used an Isky cam in that engine. When I installed the cam, I could hardly get it to turn in the block. I had to build a tool to scrape the cam bearings so the cam would turn freely. I wasn't pretty, but I had no choice. Since then, Ted and others have stated some machinists install YBlock cam bearings wrong. I have learned to never assume a machine shop knows YBlocks. It's better to assume they don't and check everything twice.
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By BamaBob - 4 Years Ago
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Other than not aligning the oil holes or not centering the cam bearing, how can a bearing be installed wrong?
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By Ted - 4 Years Ago
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BamaBob (1/23/2020)
Other than not aligning the oil holes or not centering the cam bearing, how can a bearing be installed wrong?
The cam bearing can be installed crooked or ‘cocked’ by not having the tool square when installing the bearings. The front one can be trickier than the rest in that regard if installing all the bearings from the front of the block. Or the cam bearing holes in the block can be undersized by a small degree and that in turn makes the cam bearing I.D. too small when installed.
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By Florida_Phil - 4 Years Ago
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When I took my current engine block to the machine shop, I gave them the cam I was going to use. I told them about my previous experience and asked them to make sure the cam rotated freely. It did.
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By Ted - 4 Years Ago
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The other side of this coin is the cam tunnel hole alignment. While the 272 and 292 engines have a straight through bored hole, the 312 engines are bored from each end and meet somewhere close to the middle. Some blocks are worse than others depending upon the tooling or how the block was set up in the boring fixture but many 312’s suffer some degree of cam tunnel misalignment. Put this misalignment in combination with the occasional undersized hole and you have a worst case scenario. The factory resolved this by using 0.010” undersize bearings in the 312 blocks and once installed, the cam tunnel was honed back to the correct size from end to end ending in a straight hole once more. Hence all the issues with 312 cam bearing installations when new cam bearings are installed as part of a rebuild.
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